// Framework grid generation
//
// Used only by Bootstrap to generate the correct number of grid classes given
// any value of `@grid-columns`.
.make-grid-columns() {
    // Common styles for all sizes of grid columns, widths 1-12
    .col(@index) {
        // initial
        @item: ~".col-xs-@{index}, .col-sm-@{index}, .col-md-@{index}, .col-lg-@{index}";
        .col((@index + 1), @item);
    }
    .col(@index, @list) when (@index =< @grid-columns) {
        // general; "=<" isn't a typo
        @item: ~".col-xs-@{index}, .col-sm-@{index}, .col-md-@{index}, .col-lg-@{index}";
        .col((@index + 1), ~"@{list}, @{item}");
    }
    .col(@index, @list) when (@index > @grid-columns) {
        // terminal
        @{list} {
            position: relative; // Prevent columns from collapsing when empty
            min-height: 1px; // Inner gutter via padding
            padding-left: ceil((@grid-gutter-width / 2));
            padding-right: floor((@grid-gutter-width / 2));
        }
    }
    .col(1); // kickstart it
}

.float-grid-columns(@class) {
    .col(@index) {
        // initial
        @item: ~".col-@{class}-@{index}";
        .col((@index + 1), @item);
    }
    .col(@index, @list) when (@index =< @grid-columns) {
        // general
        @item: ~".col-@{class}-@{index}";
        .col((@index + 1), ~"@{list}, @{item}");
    }
    .col(@index, @list) when (@index > @grid-columns) {
        // terminal
        @{list} {
            float: left;
        }
    }
    .col(1); // kickstart it
}

.calc-grid-column(@index, @class, @type) when (@type =width) and (@index > 0) {
    .col-@{class}-@{index} {
        width: percentage((@index / @grid-columns));
    }
}

.calc-grid-column(@index, @class, @type) when (@type =push) and (@index > 0) {
    .col-@{class}-push-@{index} {
        left: percentage((@index / @grid-columns));
    }
}

.calc-grid-column(@index, @class, @type) when (@type =push) and (@index =0) {
    .col-@{class}-push-0 {
        left: auto;
    }
}

.calc-grid-column(@index, @class, @type) when (@type =pull) and (@index > 0) {
    .col-@{class}-pull-@{index} {
        right: percentage((@index / @grid-columns));
    }
}

.calc-grid-column(@index, @class, @type) when (@type =pull) and (@index =0) {
    .col-@{class}-pull-0 {
        right: auto;
    }
}

.calc-grid-column(@index, @class, @type) when (@type =offset) {
    .col-@{class}-offset-@{index} {
        margin-left: percentage((@index / @grid-columns));
    }
}

// Basic looping in LESS
.loop-grid-columns(@index, @class, @type) when (@index >=0) {
    .calc-grid-column(@index, @class, @type); // next iteration
    .loop-grid-columns((@index - 1), @class, @type);
}

// Create grid for specific class
.make-grid(@class) {
    .float-grid-columns(@class);
    .loop-grid-columns(@grid-columns, @class, width);
    .loop-grid-columns(@grid-columns, @class, pull);
    .loop-grid-columns(@grid-columns, @class, push);
    .loop-grid-columns(@grid-columns, @class, offset);
}